在使用捏手势时，uiview的界限是否会改变？

我正在使用UIPinchGestureRecognizer来扩展/缩小uiview。

UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scaleElement:)]; [pinchGesture setDelegate:self]; [element addGestureRecognizer:pinchGesture]; [pinchGesture release]; 

//比例元素方法

 - (void)scaleElement:(UIPinchGestureRecognizer *)gestureRecognizer { UIView *element = [gestureRecognizer view]; [self adjustAnchorPointForGestureRecognizer:gestureRecognizer]; if ([gestureRecognizer state] == UIGestureRecognizerStateBegan){ lastTouchPosition = [gestureRecognizer locationInView:element]; } else if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged){ CGPoint currentTouchPosition = [gestureRecognizer locationInView:element]; CGPoint deltaMove = [self calculatePointDistancewithPoint1:currentTouchPosition andPoint2:lastTouchPosition]; float distance = sqrt(deltaMove.x*deltaMove.x + deltaMove.y*deltaMove.y); float hScale = 1 - deltaMove.x/distance * (1-gestureRecognizer.scale); float vScale = 1 - deltaMove.y/distance * (1-gestureRecognizer.scale); if (distance == 0) { hScale = 1; vScale = 1; } element.transform = CGAffineTransformScale([element transform], hScale, vScale); CGAffineTransform transform = CGAffineTransformMakeScale(hScale, vScale); element.bounds = CGRectApplyAffineTransform(element.bounds, transform); [gestureRecognizer setScale:1]; lastTouchPosition = currentTouchPosition; } if ([gestureRecognizer state] == UIGestureRecognizerStateEnded) { NSLog(@"scaling over"); NSLog(@"bounds = %@",NSStringFromCGRect(element.bounds)); NSLog(@"frame = %@", NSStringFromCGRect(element.frame)); } NSLog(@"scalePiece exit"); } //adjustAnchorPointForGestureRecognizer method - (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer { if (gestureRecognizer.state == UIGestureRecognizerStateBegan) { UIView *elementToAdjust = gestureRecognizer.view; [self.view bringSubviewToFront:gestureRecognizer.view]; CGPoint locationInView = [gestureRecognizer locationInView:elementToAdjust]; CGPoint locationInSuperview = [gestureRecognizer locationInView:elementToAdjust.superview]; elementToAdjust.layer.anchorPoint = CGPointMake(locationInView.x / elementToAdjust.bounds.size.width, locationInView.y / elementToAdjust.bounds.size.height); elementToAdjust.center = locationInSuperview; } } 

控制台打印：

 bounds = {{0, 0}, {178.405, 179.018}} frame = {{300.642, 566.184}, {192.899, 194.227}} 

为什么当边框改变时边界不能调整？ 这是否有任何与自动resize的面具，因为我有这个视图的子视图？

Answer 1

这与UIPinchGestureRecognizer 。 这与你设置transform来执行缩放有关。 更改transform不会更改bounds 。 它只是改变这个视图的坐标空间（ bounds ）如何映射到超视图的坐标空间（ frame ）。 如果您需要bounds匹配frame ，您必须直接更改其中一个，而不是使用transform 。 也就是说，你通常应该使用transform因为它更快。

编辑

如果您不想缩放，而是要调整视图的大小，请调用setBounds: 您可以通过将变换应用于bounds而不是元素来find新的bounds 。

 CGPoint currentTouchPosition = [gestureRecognizer locationInView:element]; CGPoint deltaMove = [self calculatePointDistancewithPoint1:currentTouchPosition andPoint2:lastTouchPosition]; ... CGAffineTransform transform = CGAffineTransformMakeScale(hScale, vScale); self.bounds = CGRectApplyAffineTransform(self.bounds, transform);